So, I'm in a college class, and it requires the use of photoshop. In doing so, the professor requests the .PSD file to review the history and see what we did in the process. However, in this last project, the history is gone and, nor my professor or I can view the history. It is a requirement for it to be accessible. Any help is appreciated.
You have to enable history embedding in the preferences. It's off by default to prevent bloated files. Of course make sure to allow enough history steps to be maintained in the history palette settings in the first place.